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Military Applicationsof Wearable Computersand Augmented Reality*

R. C. KasteU.S. Army Research Laboratory,

Aberdeen Proving Ground

INTRODUCTION

Computers have evolved from huge mainframes to bulky workstations anddesktops to slim notebooks and now to highly portable handheld or wear-able computers. Wearable and handheld computers have great potentialfor military use, and there is currently great interest in what these highlyportable devices can do. This chapter focuses on highly portable computingdevices, those that are wearable (belt, wrist, and head-mounted) and hand-held, and the term wearable computers (WCs) will often be used when

C. C. Tappert, A. S. Ruocco, K. A. Langdorf,F. J. Mabry, K. J. Heineman, T. A. Brick,

D. M. Cross, and S. V. PellissierU.S. Military Academy, Wesf Point

*The views expressed in this article are those of the authors and do not reflect the official policyor position of the United States Military Academy, Department of the Army, Department of Defense,or the United States Government.

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626 TAPPERT ET AL.

*The reader should be aware, however, that this field is changing so rapidly that there will besignificant changes even within publishing cycles.

referring to all these devices. The chapter briefly discusses input/outputdevices since the need for their miniaturization is one of the primary moti-vations for using WCs. It then summarizes the areas of military applicationof these devices: communications, position determination and map func-tions, report preparation and calculation, repair and maintenance, medi-cal support, and the digitized battlefield. It also discusses the wearablecomputing equipment being developed for US. Army infantry units, aprototype of which was recently tested in a recent Advanced War-fighterExercise.*

BACKGROUND: INPUT/OUTPUT DEVICES

Although miniaturization has allowed computers to become significantlysmaller, the size of conventional input and output devices is now one ofthe main factors (other factors include thermal dissipation and power sup-ply/battery size) limiting further miniaturization. Therefore, alternatives tothe traditional keyboard and monitor input/output devices are being de-veloped by the military and commercial companies and are competitivelyevolving in the civilian marketplace. These alternatives primarily concernpen computing, speech, and head-mounted displays.

Tablet digitizers (electronic tablets), available since the late 195Os, al-low the capture of handwriting and drawing by accurately recording thex-y coordinate data of pen-tip movement. Pen computing arrived whentransparent digitizers were combined with flat displays in the 1980s. Thisbrought input and output into the same surface, providing immediate elec-tronic ink feedback of the digitized writing and mimicking the famil-iar pen and paper paradigm to provide a “paperlike” interface. With apen computer (or a pen-enabled computer), users can not only use thepen (writing stylus) as a mouse but also write or draw as they do witha pen on paper. There is no longer a need for a bulky keyboard sincekeyboard entry can be mimicked by touching sequences of buttons on a“soft” keyboard displayed on the screen or, alternatively, handdrawn char-acters can be automatically converted to ASCII code by handwriting recog-nition software. Available handwriting recognition products are highlyaccurate on careful handprinting and some products are available that rec-ognize cursive script with accuracy dependent on the writing style and the

20. MlLlTARY APPLICATIONS OF WEARABLE COMPUTERS 627

regularity and clarity of the writing (Tapper-t et al., 1990; Tapper-t & Ward,1992).

Also in contrast to standard forms of input (i.e., keyboard and mouse),input based on speech recognition requires less operational work area andallows “hands-free” operation, eliminating the need for a keyboard. Forspeech input there are isolated-word and continuous-speech recognitionsystems. The simplest and most accurate systems operate only on wordsspoken in isolation (one at a time) and are text-dependent with a limitedvocabulary. Since many military applications require only a small numberof isolated commands or controls, these systems are relatively easy tocreate. Continuous speech systems are more complex and less accuratebecause they must handle the smearing of sounds across word boundaries(Padilla, 1997; Parsons, 1987).

Speech recognition systems currently available commercially include:Dragon Dictate Single, Kurzweil Voice Pad Pro, and IBM Voice Type-Simply Speaking. The first two handle vocabularies of 10,000 words, andthe IBM system handles 22,000 words. These systems recognize connectedspeech, but they do require brief pauses between words. Recent work atMicrosoft in audio recognition on a voice application program interface hasdemonstrated that continuous speech recognition is feasible on 200 Mhz +Pentium desktop systems (Microsoft, 1999.)

To be useful in battlefield applications, speech recognition hardware andsoftware must provide acceptable performance under less than ideal condi-tions, such as speakers under stress, high levels of background noise, and allweather environments. In such situations, a large vocabulary system may,in fact, not be appropriate. More appropriate for the battlefield environmentare small vocabulary, isolated-word (or short phrase) systems using noisecanceling and helmet-mountable microphones, and a 100% failsafe systemfor critical commands (such as “FIRE!“) would be imperative.

Speech output devices are also effective in WCs applications becausethey allow the user to listen, rather than divert visual attention to a monitor.Speech output can be created either synthetically or from recorded naturalspeech and such systems are readily available.

Another alternative to the traditional monitor is a Head-Mounted Display(HMD). The HMD mounts on the head like eyeglasses or goggles, providesthe user with a large virtual display visible in one or both eyes, and is smalland portable. Basically, it is a better trade-off of display size and qualityversus equipment size than other display technologies, making it ideal foruse with WCs. Many applications, including most of interest to the military,use see-through HMDs in which the display is either superimposed or, more

628 -I-. \lPl’Ef 33‘ ET AL.

usually, projected onto only a portion of the eyepiece so that the user’s real-world vision is augmented by the ability to see the displays. One such productcurrently available is Virtual I-glasses. ’ VPC from Virtual i-0. HMDs usedfor virtual reality, on the other hand. attempt to totally immerse the userin the virtual environment, and they therefore completely block the user’snormal vision.

In 1992, the Defense Advanced Research Projects Agency (DARPA)established the HMD Program with the goal of creating small, flat-panel,high-resolution displays that can be mounted in novel wa1.s to present visualinformation to personnel on the battlefield. The emphasis of the HMD pro-gram is to provide information where ordinary displays are inappropriate orimpractical: those requiring hands-free operations. where total immersionis important, and those involving unique viewing requirements. such as 3-Dimages, mappin, e0 oraphical images onto real images. and night vision. The

FIG. 20. I HhID for the [IS. ;\rrl1) .Solclic~r S~‘s1~‘rII.s (:orrlrl1:ir1(i’sLand Warrior.

20. MILITARY APPLICATIONS OF WEARABLE COMPUTERS 629

FIG. 20.2. U.S. Arm)’ Soldier S)‘stems Con~nzuxi’s Land M’arrior.

1 l-ounce Combat Vehicle Crew (CVC) goggle, already developed underthis program, incorporates a 1280 x 1024 active-matrix electroluminescentdisplay into a standard U.S. Army sun, wind, and dust goggle. The firstapplication of the CVC goggles will be for M 1 A2 tank commanders, whilelater plans include the Land Warrior (see Figures 20.1 and 20.2) and theForce XXI Soldier.

AIIILITARY APPLlCATlON AREAS

There are several aspects of WCs that relate to their use in the military.They must be rugged, and applicable military standards exist (e.g., MIL-STD-8 1 OE, Environmental Test Methods and Engineering Guidelines) tocontrol tests and testing methods for rugged equipment (Hunter, 1996).They may have docking stations. cradles or holsters for recharging, upload-ing/downloading information, providing communication, or for securingthe device and preventing damage. Battery life and other power relatedconsiderations are critical. Weight and cost are important. Finally, other

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630 TAPPERT ET AL.

features that arise from their mobility requirements include wireless com-munication and knowledge of current location.

With today’s rapid technological advances, particularly in the area ofsmall mobile computing devices, equipment designed and developed bythe usual Department of Defense (DOD) method of “full military specifi-cation” is often obsolete before it is delivered. An alternative to the “old”method, and now a DOD initiative, is to purchase commercial off-the-shelf(COTS) equipment whenever possible and, only when necessary, modifyit for military use (Herskovitz, 1994; McAuliffe, 1996). Sometimes COTStechnology can be the starting point for military computers that are modi-fied, for example, by making them more rugged (Fisher, 1996; Herskovitz,1995). Because many current applications, such as those in the transporta-tion industry, require rue0OOed computing devices, additional ruggedizationfor military purposes may not always be necessary. Although the COTS ini-tiative is causing changes in many organizations with, for example, NASAmaking extensive use of COTS subsystems (Rhea, 1996), some are sayingthat the initiative may be moving too fast and not giving proper consider-ation to unique military requirements (Wilson, 1996).

Commercially, although only about a half million wearable/handheldcomputers were sold in 1995 compared to 3.5 million notebook computers(Blodgett, 1996), their use and sale are growing rapidly and this growthis expected to continue. Pen computers, personal data assistants (PDAs),and other small computers are used extensively in industries such as trans-portation, healthcare, finance, construction, insurance, and police. Usuallyan organization begins to use these highly portable computers to gain anedge over their competitors.

As in the civilian sector, there are many military applications of PDAs/WCs. Among these are special operations, maintenance, communications,language translation, position determination, map functions, report prepa-ration and calculations, training, security, medical support, logistics sup-port, distance learning, imagery gathering, law enforcement, and recon-naissance. Several of these aspects are discussed in more detail below. Itshould be noted that many of the advantages cited in individual sectionsapply throughout.

Land Warrior

As indicated previously, a WC can be worn like a belt, vest, or bandoleer,or shaped to fit into small spaces. Such a device can be used in battle dressor with other uniforms. With WCs there is no need to shuttle between

20. MILITARY APPLICATIONS OF WEARABLE COMPUTERS 631

computer workstation and operational site for information processing.These devices can also reduce the need for bulky paper documents.

The Land Warrior (see Figure 20.2) is an integrated fighting systemfor dismounted soldiers. Its purpose is to enhance the individual soldier’sability to survive in adverse conditions, acquire and engage targets, andbecome fully integrated in the digitized battlefield. It consists of fourphysical subsystems and a software subsystem (Aninger, 1996). The in-tegrated helmet assembly subsystem consists of a helmet-mounted com-puter and sensor display by which the soldier can view digitized maps,intelligence information, and imagery from a thermal sight on his/herweapon. The equipment and protective clothing subsystem consist of abackpack frame that bends with the soldier’s natural body movements andbody armor that offers improved ballistic protection at a reduced weight.The weapon subsystem includes a thermal sight, video camera, and laserrangefinder/digital compass, which can be coupled with the Global Posi-tioning System (GPS, described later) to provide extremely accurate po-sitional and targeting information. The computer/radio subsystem, builtinto the backpack frame and integrated with GPS modules, consists of tworadios (one for communicating with other soldiers within the squad, theother for communicating outside the squad) and a menu driven computerinterface, controlled by a pointing device located on the chest strap. In sum,the Land Warrior program will enhance the soldier’s battlefield capabilitiesthrough the development and integration of these subsystems, merging thesoldier and technology into a cohesive, combat-effective system (Army,1996).

Communications

One of the commander’s main requirements is communications. That is, hemust advise subordinates of changes in mission, support, and threat; also,he must inform superiors of changes in threat or timelines. The WC cansimplify this procedure. Consider a company conducting a reconnaissancemission to note concentration, activity, and location of enemy defenders,washed out bridges, and/or battle damage. If the commander immediatelyreports the information by combat net radio, his emission alerts the enemyas to his presence; if he waits until returning to headquarters, his informationwill likely be stale. A remedy is to input the information into a WC, andat the first safe opportunity, use it to update the database on which suchinformation resides. Communication can be facilitated by antenna arrayssewn into clothing associated with the WC.

632 TAPPERT ET AL.

The Army’s Communications Electronics Command (CECOM) at FortMonmouth predicts that by 1999 every soldier will be issued a small com-puter. They are currently experimenting with a rugged handheld computercalled “The Grunt” that fits into the thigh pocket of the battle dress uni-form (BDU). It communicates with satellites, runs complex software, andoperates by fingertip on a touch-sensitive screen to eliminate the needfor a keyboard (Matthews, 1994b). Such mobile computing devices in thehands of individual soldiers may be tomorrow’s combat “force multipliers”(Glasser, 1997).

With the current trend toward multinational missions, communicatingwith automatic language translation becomes extremely important. Evenwhen forces of various countries are separate, translation is vital in co-ordinating operations, both at headquarters, where such coordination isroutinely performed, and also at the fighting level, where functions suchas unit boundary development and field of fire coordination are addressed.There are several software options that can provide support in this area. Forexample, the Psion Series 3 PDA with Berlitz Interpreter permits translationof 28,000 words among five European languages (Psion, 1998).

Position Determination andMap Functions

In many operations it is necessary to know one’s location accurately. Forexample, only when the location of a field artillery battery is properlysurveyed and stored can gun orders be calculated. Moreover, one certainlywould not want to call for artillery fire without accurately knowing one’sown location! The Global Positioning System (GPS) was designed for andis operated by the U.S. Military. Twenty-four satellites orbit the earth in12-hour orbits to provide the user with five to eight satellites visible fromany point on earth. They send ephemeris data to GPS receivers over radiosignals. GPS receivers require input from at least four satellites and convertthe radio signals into x-y-z position and time. The primary function of GPSis navigation in three dimensions (latitude, longitude, and altitude). Velocityand acceleration are also easily computed.

Precise Positioning System (PPS) data can only be received by govem-ment-authorized users with cryptographic equipment and special receivers(20 meter accuracy). Standard Positioning System (SPS) signals, inten-tionally degraded by the DOD, provide decreased (100 meter) accuracy tocivilian users that can be captured by most receivers without charge or

20. MILITARY APPLICATIOSS OF ~IF/Il<,~2131~~~ (:OIlI’I -I‘I.ZRS 633

restrictions. Differential GPS techniques can be used to correct bias errorsat one location with measured bias errors at a known position, therebyincreasing the accuracy of the data (differential SPS, for example, canobtain l-10 meter accuracy).

As for the receiver, the Army is in the process of fielding the Preci-sion Lightweight GPS Receiver (PLGR, AN/PSN- 1 1). The PLGR is asmall, handheld, GPS receiver featuring selective availability/anti-spoonng(!&4/A-S) and anti-jam capability (see Figure 20.3). It provides precise

FIG. 20.3. Precisior\ Ligl>t\z’c’igi 11 (;I ‘5 RcYI‘I\‘~‘~ (PLGR).

6 3 4 TAPPERT ET AL.

positioning and timing solutions based upon signals received from theGPS satellite constellation. It is a five-channel receiver, capable of Preci-sion Code (P Code) and Y Code (encrypted P Code) reception. Positioningsolutions can be displayed in latitude, longitude, military grid referencesystem, Universal Transverse Mercator, British National Grid, and IrishTransverse Mercator Grid coordinates. It contains 49 map datums, can beprogrammed to support navigation, and has a built-in test feature.

Some commercial GPS products are stand-alone units used primarily forair, sea, and land navigation that receive thex-y-z location and time data andperhaps display the location on a chart or map. Some car rental agencies,for example, are beginning to add this equipment in their vehicles. OtherGPS products are sold as add-on equipment for handheld and notebookcomputers.

Because the display of the PLGR is alpha-numeric only, the soldier mustread the display and correlate it to his or her map. Alternatively, this can alsobe performed quickly and conveniently with FieldWorker software. Actingas a bridge between the GPS and a computer’s operating system, it providesrapid flexible data collection, along with equipment linkage testing and GPSaveraging (Apple, 1997). Along that same line, cadets at the United StatesMilitary Academy (USMA) recently participated in a project that involvedtaking data in real time from a PLGR and displaying the PLGR’s locationon a moving map displayed on a laptop computer screen. A map of WestPoint was digitized and a moving map software program that used VisualBasic was developed to display the user’s location on the map. As the unitmoved, the map was redrawn to indicate the movement, maintaining thecursor in a centralized position on the map.

Moving from one location to another is an integral part of operationssuch as attack and force consolidation. The manner and route of such move-ments should be determined in advance to avoid increased vulnerability toenemy fire and delays created by terrain, congestion, and excessively longroutes. Route planning can be facilitated through WC capabilities that havebeen used in civilian applications. One software package, Microsoft’s Au-tomap Road Atlas, has 400,000 miles of North American highway data.On entering start and destination, Automap responds in seconds with thefastest, shortest, or preferred route; provides step-by-step instructions; andplots a customized map (Microsoft, 1998). Some research and develop-ment effort would be required to convert the commercial version, uti-lizing a network of distance and speed data, to military route planning.For example, a military version would have to store factors associated

20. MILITARY APPLICATIONS OF WEARABLE COMPUTERS 6 3 5

with a two-dimensional space, vehicle and surface types, weather con-ditions, etc.

Report Preparation and Calculations

A commander must routinely send reports throughout the chain of com-mand with respect to various items such as target sightings, troop movementplans, ammunition availability, casualties, incoming fire, and maintenancerequirements. A WC could help the commander by allowing him to com-pose such reports (or insert the date in formatted templates) in momentswhen his presence is not immediately required in battle management ac-tivities. The use of a WC also has the advantage of not constraining himto the location of his main battlefield computer/communication systems.A system such as the MessagePad, with compatible software, could easilybe used for report preparation.

At some point, every commander finds some of his time expended bysimple mathematical calculation. He must frequently perform tasks likedetermining north alignment for gun emplacements, estimating the timewhen his fuel will be expended, determining magnitudes of disparitiesbetween his operations orders and current status, estimating when he willbe required to move his position, etc. These functions can be performedwith a handheld calculator, but the WC would help the commander byfacilitating the input and output.

Repair and Maintenance

See-through HMDs are currently being used for vehicle and other repairtasks. The Navy, for instance, is using a belt-mounted computer and HMDunit for helicopter maintenance, and the Army is putting 147 Ml tankmaintenance manuals onto CD-ROMs for use in WCs. The user reads in-structions and sees diagrams concerning the necessary repair in a displayprojected onto a small portion of his eyepiece and can work on the repairwithout shifting his focus of attention. Other uses of this equipment mightallow a soldier coming up a hill to see in his eyepiece images transmit-ted from an unmanned aircraft of what lies on the other side of the hill(Matthews, 1994a). NASA has been using mobile computing since the firstspace shuttle flights. They currently use wireless units and pen comput-ers to help with navigation and to help the crew monitor experiments andoperations (MacNeill, 1996).

636 TAPPERT ET AL.

Medical Support

To an extent, the PDA has replaced reference books and patient index cards.Its main capability has been automation of ancillary tasks, giving the physi-cian more time to practice medicine. The medically oriented PDA is nowa specialized tool for managing large amounts of information. EducationalResearch Laboratories, Inc., has released a number of texts and handbooksin electronic format that can utilize the Newton’s built-in search func-tions, thereby making it easy to cross-reference information. In the realmof patient management, PocketDoc by Physik, Inc., helps automate clin-ical experiences by allowing information to be handwritten directly intothe database and handed off conveniently. There are other PDA options,including: Med-Notes, allowing quick point-of-care collection of patientinformation; Medicine Series, accessing the complete contents of refer-ences for medical residents; and PocketDoc Practitioner, a mobile recordsystem designed to mimic the workflow of physicians (Manse11 & Cogle,1996).

On the battlefield, the first hour after a soldier is wounded is the mostcritical for patient care. Today’s soldier can expect rapid transport from thebattlefield to a hospital via aircraft; however, he or she must still wait for amedic to arrive, assess the situation, provide initial treatment, and have anaircraft dispatched. To expedite this process, one alternative is to bring thehigher technology to the soldier.

In addition to answering the dismal question of whether a soldier isstill alive, analysis of a soldier’s vital signs, specifically heart rate andbreath rate, serve as indicators of a soldier’s immediate general health(e.g., current level of fatigue, stress, anxiety, etc.). If this analysis weredone on a continuous basis and monitored remotely, it could assist superiorsin assigning the best qualified personnel to a given mission. The AcousticSensor Division of the Army Research Labs (ARL) is developing a medicalmonitoring device that has a liquid filled acoustic sensor pad to detect thesephysiological sounds (Siuru, 1997).

The sensor pad has close to the same density of the human body andthe surface material is close to that of human skin. Thus, when placed incontact with the human body, the pad provides good acoustic couplingbetween the person and the hydrophones embedded in the pad. The hy-drophones produce a low amplitude analog signal that is amplified andpassed through an analog-to-digital converter to create a digital represen-tation of the physiological sounds. This signal is processed in the WC bydigitally filtering to allow only the low-level heart and breath sounds to

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20. MILITARY APPLICATIONS OF WEARABLE COMPUTERS 637

remain and performing Fourier analysis to separate heart and breathingsignals for display if necessary.

Each soldier will be equipped with such a medical status monitor thatconstantly reads blood pressure, pulse, respiration, and blood oxygen level.A built-in expert system will determine when the soldier’s condition war-rants attention and automatically transmits an alarm, including GPS loca-tion and possibly injury severity.

Since there is a limit to the complex equipment a medic can carry, ARLand the Medical Advanced Technology Management Office are developingthe Mobile Medical Mentoring Vehicle (M3V) (Balakirsky, 1996). Insidethe M3V a physician’s assistant and dispatcher are in charge of medicaloperations. The dispatcher alerts a medic in close proximity to the casualtyover the Medic-cam (discussed below), notifying him of the location ofthe wounded, the conditions, and best route. In addition, actual coordinatesare downloaded into the medic’s WC. By integrating GPS with this route,the medic is given direction and distance indications to the wounded. Themedic’s video signal is compressed by his WC using a lossless scheme toavoid losing detail important for the physician. The medic’s feed is con-trolled by a voice-activated interface and displayed on a monitor in theM3V. The assistant can retrieve an electronic inventory of what the medicis carrying and choose the most appropriate medication. The medic scansthe barcode on the medication package, with the information automati-cally transmitted to the M3V, where it is incorporated into the treatmentrecord.

Expertise from the M3V or even more distant medical centers will beobservable through the use of the Medic-cam. The medical expert willremotely see and hear the patient and observe the output from the med-ical monitors. The Medic-cam comprises mainly a pencil video cameraon glasses worn by the medic and electronics located on his load-bearingequipment. His voice is picked up by a flexible boom mike; audio reacheshim through small earphones. A view screen positioned under the medic’seye allows him to see the image being transmitted. A WC, tactical com-munication links, and long-life batteries are currently under investigationfor this system.

On a much larger scale, the Telemedicine Acquisition Initiative providesthe Army Medical Department (AMEDD) with the latest communicationcapability to support field medicine from the forward edge of the battlefieldto the continental United States. From reading diagnostic images to visu-ally inspecting patient conditions with direct consultation links, AMEDDexperts can participate in treating patients anywhere in the world.

638 TAPPERT ET AL.

Distributed Data Fusion

The military intelligence process concerns the collection, analysis, andinterpretation of information to answer a request for specific intelligenceconcerning an area of interest. There are three corresponding information-processing tasks: data fusion, situation analysis, and countermeasure plan-ning. Data fusion is the process of assembling a model of the domain ofinterest from disparate data sources and has three main characteristics:multi-sensor data fusion, uncertainty, and continuous process (Keene &Perre, 1990).

Data fusion represents the consolidation of data that are received fromsensors. The data are consolidated, typically using some probabilisticmodel, to form a view of the area in question. One method of data fusionestablishes a tree-structure hierarchy that identifies which levels performwhich type of data reduction. Measures of effectiveness (MOEs) for datafusion concern the underlying probabilistic models being employed in thevarious fusion processes (Broman & Pack, 1994).

It is possible to use a “standardized template” based on the predicteddata. These templates are based on previous studies of how forces typicallydeploy, such as predicting force structure entering your geographic areabased on the sensor data (Mikulin & Elsaesser, 1994).

As described, data fusion is a one-way process; that is, data from sen-sors are taken in raw form and sent to the next level in the hierarchy.Each subsequent level continues to process these data. However, each levelbrings with it a degree of uncertainty. The top level, within the Army’sAll Source Information Center (ASIC), is the first time an assessment ismade. This hierarchy is clearly delineated in Figure 20.4(a) (Keene &Perre, 1990).

Evaluations of the assessment are based on how well the assessmentmatches the reality. Yet, there is a substantial opportunity for the situationto change between the sensors acquiring data and the ASIC producing in-formation. This is why the fusion process must be considered a continuousprocess. However, in order to stabilize the situation to allow a template tobe utilized, a decision must be made to more or less freeze the input. At thispoint, the template may be employed as described by Mikulin and Elsaesser(1994). However, when model verification takes place, an inherent factornot mentioned in the referenced documents (Mikulin & Elsaesser, 1994) isestablishing this “freeze” point. In other words, if a template matched thesituation, did the template match because it accurately reflected the situ-ation, or did the model match because the situation had not been allowed

Situation Assessment:Centralized in the ASIC

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Data Fusion of Sensors

5Validation of sensor data for future

verification of models, sensorplacement, etc.

Situation Assessment: Quick accessto processed rather than raw data

20. MILITARY APPLICATIONS OF WEARABLE COMPUTERS 639

FIG. 20.4. Proposed modification to data fusion model: (a) thecurrent hierarchy of one-way flow between hierarchy regions, and(b) utilizing handheld devices or WCs in a tweway linkage of hier-archy regions.

to develop to a point where a different template would have been moreappropriate?

One reason there is an acceptance of the one-way nature of data fu-sion is the problem of integrating all forms of data. Human Intelligence(HUMINT), Communications Intelligence (COMINT), and ElectronicsIntelligence (ELINT) are fundamentally different types of sensors. Thus,the centralized assimilation in the ASIC seems the natural approach. Unfor-tunately, such a natural approach lends itself to having decisions madefar removed from where data have their most reliable reading. Obviously,it is not possible to place a person at every sensor location. Yet the adventof WCs may allow for the insertion of decision makers at different pointsin the hierarchy, such as a two-way link within the hierarchy as depictedin Figure 20.4(b).

Figure 20.4(a) shows the traditional flow of data from the sensors tothe ASIC. This is a one-way flow. After the ASIC makes an assessment,overall verification takes place outside the model. By using WCs, severalpossibilities identified in Figure 20.4(b) become evident. First, a decisioncan be made earlier in the process. For example, the information previouslyavailable only at the ASIC level can be transmitted to a handheld or WCoperating in the “sensor” level of the hierarchy. Assimilated data from theASIC can be based on data coming from the sensor at the fusion levelof the handheld or WC. If the data are consistent, the ASIC can continueprocessing along its current models. However, if the data coming from thesensor show a significant difference, then the ASIC can immediately betold to recalculate for more suitable models based on current data. In thisscheme, the handheld is bypassing some of the higher levels of the sensor

640 TAPPERT ET AL.

region of the hierarchy. Thus, data from the lower portion of the hierarchyare weighed more heavily in this instance.

Such a weighing, though, is not represented by any of the measuresidentified in Broman and Pack (1994). Under the current MOEs, any datapoint is assumed to have the same value to the overall fusion process as anyother data point. Obviously, then, the MOEs need to be adaptable to thepotential of some data points being more “important” than others. Hence,the insertion of handhelds or WCs into the hierarchy influences the overallfusion process in terms of MOEs. How such MOEs would be modified,however, remains to be determined.

Related to weighing various sensor inputs is the coupling of confidencefactors to possible template models. As described in Mikulin and Elsaesser( 1994), a template is selected based on the results of computing several con-fidence factors. These confidence factors are algorithmically determinedbased on matches between the sensor-driven establishment of unit loca-tions against a database-driven location of where a unit should be, basedon the doctrinal template. The doctrinal template is established based onthe correlation of the template to actual circumstances. This implies, then,that the doctrinal template is the end result of all the times that templatehas been selected. Thus, if a template is selected, and it does not match thereality of the situation, there are two negative effects. The first is that thewrong actions may be taken at the tactical level. For example, preparing fora unit of Type-A when it is actually a unit of Type-B. The second negativeeffect is that the template may be adversely adjusted due to an outlier dataentry, that is, the wrong application.

Using WCs within the hierarchy can help eliminate such adverse effects.The WC can receive potential templates from the ASIC. Utilizing fuzzy-logic techniques, the WC can perhaps be used to backward engineer thedata required for a template to have a high confidence factor. Again, theWC is used to bring the decision closer to the data-entry point in the fusionprocess.

Once the theoretical justification is made, an experimental environmentwould need to be established wherein testing resources (both hardwareand software) could actually model the proposed hierarchy. This would beestablished based on using the WC as proscribed for a given level of thehierarchy. It would be best to assume the WC is not at the sensor level.If it were, one would have in effect substituted a person for the sensor,thus discounting the need for sensor fusion. By the same token, the WCwould not be used within the ASIC, since other more powerful equipmentis already at work on the assimilation of the data. Hence, the WC insertion

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into the hierarchy would have to be tested at some intermediate level (orlevels).

As commonly shown in military exercises, the need to transmit data tothe end-user is critical to swift decision making. This results in a two-wayproblem. The data being fused together results in a consolidation fromthousands of points into a single, logical view of the battlefield. This viewof the battlefield is then broken out and transmitted back down to units. Theeffective use of WCs, properly incorporated into the data fusion pyramid,can build the local picture by accessing data on its way up to the highestconsolidation level. This will significantly reduce the time from data captureto information distribution.

Tactical Internet Applications

Just as the marketplace has generated new opportunities with respect toWCs for the military, it has also provided new ways to tie these computingelements together to develop new types of networked applications. Howthe military will actually link different information system componentstogether and use the combined set of systems will be driven to some extentby commercial developments, particularly the Internet.

Presently information systems are constructed on the Internet utilizinga client/server architecture. This is a relatively recent shift in the generalarchitecture of such systems. Beginning in the 196Os, central, time-sharedcomputing systems used terminals (with varying levels of intelligence).This architecture continued into the era of the personal computer. Twenty-five years later, by approximately 1985, the general corporate computingarchitecture had begun the conversion to a PC/file server architecture. Then,within a short eight years (198%93), that architecture was replaced by thepresent client/server architecture. This 25 to 8 ratio of change suggeststhat not only is more fundamental change coming, but that it is comingfaster than ever before. In fact, after just four years, even the client/serverarchitecture is now suggested as giving way to Network-centric applicationdevelopment (Netscape, 1996). The benefits and problems associated withthe present architecture impact the way WCs will ultimately be interfacedand the context in which they will be used in corporate America and tosome extent in the military.

A number of benefits have emerged from the client/server architec-ture that impact wearable computing applications and how they are in-terfaced and integrated into computing environments: scalability (there areno “power of computing” limitations that suddenly appear, as a solution

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is scaled up for use by more simultaneous users), cross plagonn compati-bility (the same functionality is available on a wide variety of platforms),interoperability is established at a machine family level (i.e., multi platformsupport is designed in at a low level on a machine-specific basis rather thanbeing added as conversion software or a gateway interface), reusability,reliability (with graceful degradation), and extensible functionality to newalternative uses.

This new architecture is not without its difficulties, among which arethe unpredictability of user computing requirements (particularly whencompared to prior architectures) and the need to support multiple protocolson each potential computing platform. To a significant degree, the problemsthat have been the good-news/bad-news of the commercial marketplacehave carried over to the military computing context. Several of these topicsare further expanded below.

Certainly, the most important development that will impact the migrationof Internet technology to the tactical Internet is XML. In two years (1998-2000) the extensible markup language has become the lingua franca ofInternet middleware computing (Cover, 2000). All current Army databaseserver software vendors provide support for XML based import and export.The segregation of content data from presentation data is allowing PDAcomputing to incorporate integrated data sources and display that data ina manner that best uses the limited visual area common in WC’s (Moeller,1997).

Other emerging commercial areas of development with potential impacton military computing applications of WCs include: roaming; off-line use;on-demand access; push technology; digital TV regulatory announcements(digital TV by 2006); intelligent objects; content replication capabilities;dynamic recovery with real-time, expert system driven load reallocation;“Crossware” cross everything applications; “Netcasting” (server side) andrecasting; client systems with multiple, cooperating, (possibly) distributedagents acting for the individual or the unit that the individual leads orrepresents (this is a different orientation of design and interpretation of in-tentionality than would traditionally be considered in a top-down design!);dynamic collaborative systems; and remote location configuration and sitemanagement.

Areas of potential interest that are suggested by military informationsystems development with respect to Internet and WCs include: dynamicevaluation of the proximate location of required minimal computationalfunctionality (i.e., find the nearest, in time and/or space, system that cansupport the needed computation or interaction); maximum “thickness” of

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client software within a particular type of device; flexibility and reliabilityof Simple Network Management Protocol (SNMP) functions (as SNMPfunctionality expands, it may prove necessary to proxy some functions toavoid the occurrence of unnecessary or potentially dangerous communi-cation traffic for a combat/military environment); and the need to bringnew technologies that are applicable to a military computing environmentquickly, and cleanly, in a maximally pervasive manner.

As discussed in the Data Fusion Section, communication delivery andenhancement concerns focused by the nature of military computing neces-sitate that communication support functions integrate data from a varietyof sources such as traditional audio, visual (video in many forms), groundsensory systems, and satellite systems. Such data streams may be used toimplement new communication supports: virtual conversations (for exam-ple, if a particular situation occurs, a prespecified command conversationis available for the soldier who is “on the spot!“); distributed display ofintegrated information from many sources (from real-time sensors on theground to satellite downlinks, to audio [both real-time analog and digital],to video and artificial intelligence enhanced video, to virtual reality-likesituational simulation based on available data and knowledge of enemydoctrine and tactical context); temporally disjoint communication supportthat would allow the review of recent similar communications from tem-porally indexed digital archives of analog communication); and SituationReport (SITREP) display of the combat zone with communication and sta-tus inforrnation from combat units being accessed in a “point and hear” ora “pomt and see” manner (with the level of “information freshness” alsodisplayed); nontraditional forms of command transmission that might in-clude a simulation of the action that is expected to occur and which is usedby each level of the command chain to interpret their situation, needed re-sources, tactical alternatives, etc. This simulated course of battle commandmight be able to continue its “performance” by integrating real-time infor-mation about the actual battle and providing insights into how to respondto initial results even when communication with higher command elementsis infeasible, difficult, or even dangerous.

When improvements to network-based applications force system rescal-ing, two strategies are possible (both may be employed simultaneously).First, assume use of “thin clients.” That is, forcing a few servers to growby a factor reflects the maximum dynamic user demand possible at anyinstant. Alternatively, assume use of “thick clients;” forcing all client ma-chines to “grow a little,” which may result in a “trickle down effect”to end-user systems, which is unacceptable. Interoperability should be

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achieved by vendors providing direct native support for a particular plat-form or cross platform support. Relative to the client/server architecture,support for nontraditional, non-PC devices should be done in such a waythat new devices are fluidly integrated with those already in use in themilitary.

Wireless local area networks (LANs) are a new and exciting additionto the realm of networking, particularly with WCs. Wireless LANs offercheaper installation costs than wired networks, as well as scalability androaming. However, although they are easy to install and configure, theirthroughput may be too limiting to offer a suitable substitution to existingwired networks.

CONCLUSION

Much research is still needed, but new modes of human-computer interfacewill certainly be developed. For example, input may be via the wearer’scamera tracking a “finger mouse.” A worn computer that is constantly at-tentive to the wearer and the environment would assist the wearer withperceptual intelligence in daily activities. A sophisticated WC has poten-tial as a “visual memory prosthetic” or perception enhancer, enabling thewearer to see things otherwise missed and to better remember items ofnote. Visual filters can be incorporated to study the otherwise unseeable;a freeze-frame capability, for example, would enable seeing propellers inmotion. The user might transmit a sequence of images to show colleagueswhere he or she has been, in a kind of shared visual memory. HMDs couldalso computationally augment visual perception in real time. For example,virtual images could have attached labels for easier processing in a com-plex field environment. A community of wearers could have a networked“safety net” via the ability to see exactly what others see or by monitoringeach other’s physiology (Mann, 1997).

Voice recognition as an input alleviates the need for manual interfaces.Hands-free operation generally means less time is required for data entryand retrieval. Heads-up displays permit simultaneous operation of variousoptions without keyboard or mouse. The screen can be variously visibleor overlay the real-world scene for textual or graphical processing. Minia-turized into eyeglasses, the unobtrusive apparatus permits interaction bothwith the computer and other personnel. Many devices include connectors tosupport PC peripherals such as mice, keyboards, VGA video, serial ports,and audio I/O. Some permit plug-and-play enhancements.

20. MILITARY APPLICATIONS OF WEARABLE COMPUTERS 645

Clothing is a natural way to carry a processing device, and by wearingthe device it is always ready for use. Component miniaturization has en-abled wearable systems that are almost invisible, so that the user can moveand interact freely. A number of military functions could be performedmore readily or efficiently with the use of WCs. These devices will con-tinue to gain social acceptance due to improved miniaturization and theproliferation of similar devices, such as cellular phones and pagers.

Future network application system support “improvements” cannot dic-tate operating system updates that demand more powerful hardware. Newfunctionality must not be achieved at the cost of continued compatibilityconflicts with in-place technologies already deployed-and-trained in theactive military forces. The more ubiquitous a system is to the military, themore the military will be wary of “improvements” or changes. Concerningthe tactical intemet, the importance of network-centric applications is be-ing emphasized at the undergraduate level in many universities, includingUSMA. Here, for example, all plebes (freshmen students) develop their ownhome pages and many senior-level systems design projects involve the de-velopment of Internet or intranet-based applications and, in the near future,thin-client wearable/handheld computers will be used in many projects.

In March 1997, the Army conducted an Advanced War-fighter Exercise(AWE) at the National Training Center, Fort Irwin, CA (AUSA, 1997a;Time, 1997). The AWE put many of the Army’s newest high-tech sys-tems to the test. In particular, the light infantry soldiers were equippedwith the dismounted soldier system unit (DSSU), an experimental WC andcommunications system, using a variety of commercial and governmentcomponents. While the infantry soldiers reported that the DSSU enhancedtheir communications capabilities, they also found it heavy, bulky, andfragile (Griggs, 1997). The DSSU, however, is not intended as a fieldablesystem; instead, it is serving as a prototype for the fully integrated, smaller,and lighter Land Warrior system, which the Army plans to start fieldingin the year 2000 (Aninger & Hubner, 1997). The initial outcome of theAWE test indicated a draw (Wilson, 1997), but the Army’s leadership anddoctrine writers will undoubtedly study this exercise well into the future.

General Hartzog, then Chief of the Army’s Training and Doctrine Com-mand, stated that the 2 1 st Century Army must have information dominanceon the battlefield (AUSA, 1997b). The AWE is at the heart of determiningfuture requirements, and the Army plans to field a completely digitized di-vision by 2000. That “Experimental Force” will test and measure the impactof information technology on future combat in terms of communications,computer hardware, and software (AUSA, 1997~).

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The United States Military Academy has the mission of producing lead-ers capable of meeting the rapidly changing face of technology in today’sArmy. West Point student and faculty research can and should focus onthe future needs of the Army. By using existing ties between the Academy,ARL, and other research centers, new ideas can be explored by initially de-veloping them, and then turning the results over to the appropriate agenciesfor further development.

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